His success is owed in large measure to economic populism, his clout as Democratic leader and his personality. Daschle is known for visiting each of South Dakota's 66 counties every August, his strong constituent service operation and his ability to help South Dakota farmers win government aid for their crops.
Becoming majority leader after Sen. Jim Jeffords, Ind.-Vt., decided to caucus with Democrats, Daschle was the point man for Democrats who sought to temper President Bush's agenda and advance proposals of their own. The events of Sept. 11, 2001, changed the tenor of his leadership and forced Democrats to ratchet down their criticism of the president. Daschle directly experienced terror when his office received an anthrax-laden letter.
In 2002, Democrats began to take the legislative offensive more fully, seizing on corporate scandals and a ballooning deficit to claim that Republican policies prevented an economic recovery. Daschle was instrumental in ensuring that a corporate responsibility bill passed both chambers.
But in the fall, he was criticized for his inability to articulate a simple economic counterproposal to the president. And his tenure as majority leader was cut short by the Democrats' loss of the Senate in the November midterm elections.
His addition to the presidential race would have significantly crowded the field; he shares an ideology and a base of support with Rep. Richard Gephardt, D-Mo., who announced his exploratory committee last week.
Focusing on Winning Back the Senate
With his focus on the Senate, Daschle will be able to spend time raising money and recruiting qualified candidates for 2004.
"The nation would have loved you as a presidential candidate," Sen. Charles Schumer, D-N.Y., told Daschle. "But now you're with us."
"And wouldn't it be nice if, with such a tight margin in the Senate, in 2004, if Democrats win it back, he'd be the Senate majority leader again," said Todd Taylor, an influential Iowa Democrat and member of the state's Legislature.
Democrats had worried that if too many party leaders ran for president, the fund-raising well would quickly dry.
At 9:30 this morning, Daschle telephoned his friend Tim Johnson, the junior Democratic senator from South Dakota, and said that the two would continue to serve together.
A little while later, he told Gephardt.
"I'm grateful to count Tom as a treasured friend and colleague and I am particularly grateful today that I won't be facing him in a presidential debate," Gephardt said.
Daschle finds himself in a strong position to seek re-election. Two Republican House members — John Thune, who lost a tight race for Johnson's in November, and newly elected member at large Bill Janklow — had expressed interest in running for Daschle's seat if it would be open.
"Certainly Sen. Daschle is a formidable opponent," said Laura Schoen, executive director of the South Dakota Republican Party.
And Republicans may yet get the chance to take on Daschle as a presidential candidate.
"There may come a time in my future that a national candidacy is something that I will entertain," he said.
"I relish the idea of a campaign but I have one at home," he said. "And I'm looking forward to that."
ABCNEWS Political Director Mark Halperin, and ABCNEWS' Linda Douglass and Elizabeth Wilner contributed to this article.